1. Field of the Invention
The invention relates to a high pressure fuel pump with a pressure relief valve.
2. Description of the Prior Art
A high pressure fuel pump of the type mentioned at the beginning is known from DE 10 2004 013 307 A1. In this one-cylinder piston pump, the delivery chamber can be connected to a high pressure outlet by means of a spring-loaded outlet valve. Fluidically parallel to the outlet valve, a pressure relief valve is provided, which has a spring-loaded valve ball as a valve element. The pressure relief valve opens toward the delivery chamber and, when open, connects the high pressure outlet to the delivery chamber. A pressure relief valve situated in such a way has the advantage that it protects the high pressure region from impermissibly high pressures, but simultaneously does not reduce the volumetric efficiency of the high pressure fuel pump since the pressure relief valve only opens when the pressure prevailing in the delivery chamber is significantly lower than the pressure in the high pressure outlet.